A simultaneous perception type far and near contact lens 100 is known, in which a distance portion 102 for aiding far vision is disposed in the center portion of a lens optical region 101, a near portion 103 for aiding near vision is disposed in the peripheral part of the lens optical region 101, and an intermediate portion 104, in which a power gradually changes, is disposed between the distance portion 102 and the near portion 103 in the far and near contact lens, as shown in FIG. 12, and the power in the lens optical region 101 is distributed in a concentric circle (Patent Document 1).
A bifocal alternating-vision contact lens is known, in which a distance portion is provided in the upper part of the lens optical region, and a near portion is provided in the lower part in the far and near contact lens, as described in Patent Document 2. A trifocal alternating-vision contact lens is also known in which a distance portion is provided in the upper part of the lens optical region, a near portion is provided in the lower part, and an intermediate portion is provided between the distance portion and the near portion in the far and near contact lens, as described in Patent Document 3.
[Patent Document 1]
JP-A 59-208524
[Patent Document 2]
U.S. Pat. No. 4,693,572 Specification
[Patent Document 3]
UK Patent No. 1025677 Specification